PhWiki is a new wiki that uses rcs, Smarty templates and the Text_Wiki PEAR module for Wiki parsing.  It is very modular and customizable.  I've made an attempt to reuse as much code as possible from other projects, simply providing the "glue" that hold's them together.  PhWiki is very easy to install and configure.
( BrokenLink )

There are many unimplemented features right now such as security, page revision rollback, etc., but they should be easy to add quickly.  You can check out the PHWikiBugs page on the site if you wish to request something.

PhWiki is released under the GPL license.

Apparently PhWiki has disappeared from the scene. The site is now running DokuWiki.